ES2275625T3 - POLYCHONDENSATION OF POLYESTERS WITH TITANIL OXALATE CATALYST AND A CATALYST POTENTIATOR. - Google Patents

Abstract

The present invention is based upon the discovery that nontitanyl oxalates can enhance the catalytic functionality of titanyl oxalate catalysts. This invention provides anovel catalytic composition containing a titanyl oxalate catalyst and a metallic oxalate catalyst enhancer and optionally containing a metallic cocatalyst such as an antimony based catalyst, A synergistic relationship has been discovered between titanyl oxalate catalyst and the catalyst enhancer. A synergistic relationship has also been discovered between the titanyl oxalate catalyst, catalyst enhancer and a metallic cocatalyst such as antimony oxide or antimony triacetate. Also provided is an improved process of producing polyester by the polycondensation of polyester forming reactants in the presence of a catalytically effective amount of a polycondensation catalyst, wherein the improvement comprises utilizing, as the polycondensation catalyst, the novel catalyst composition containing a titanyl oxalate such as lithium titanyl oxalate and a catalyst enhancer such as a nontitanyl metallic oxalate like lithium oxalate and optionally containing a metallic catalyst such as antimony oxide or antimony triacetate. The improved process produces an improved polyester having lower acetaldehyde numbers and good color. The titanyl oxalate/catalyst enhancer composition can be used as a polycondensation catalyst in combination with other catalysts to achieve synergistic catalytic activity. Preferred is a combination of lithium titanyl oxalate, Li2TiO(C2O4)2, lithium oxalate, Li2(C2O4)2 with antimony oxide or antimony triacetate or antimony trisglycoxide.

Description

Polyester condensation with catalyst titanyl oxalate and a catalyst enhancer.

Background

The invention relates to a method for manufacture polyesters, in particular using a titanyl oxalate, such as lithium titanyl oxalate, as catalyst of said reaction in combination with a catalyst enhancer such as a metal oxalate such as lithium oxalate that provides quick reactions as well as better properties such as a lower acetaldehyde content and good properties of color of the resulting polyester at catalyst levels substantially smaller. A synergistic relationship has been discovered between the titanyl oxalate catalyst, and an enhancer of catalyst. A synergistic relationship between the titanyl oxalate catalyst, the catalyst enhancer and a metal cocatalyst such as antimony oxide or the antimony triacetate.

The polycondensation reactions they produce Polyesters require an extremely long period of time that It is significantly reduced with a suitable catalyst. Are used various types of catalysts to decrease the time of reaction. For example, as polycondensation catalysts antimony trioxide, antimony triacetate is usually used and antimony tris glycoxide.

The titanyl oxalate compounds have been suggested as catalysts in polycondensation reactions to produce polyesters. However, oxalate catalysts of titanyl when they have been used as catalysts for polycondensation for the manufacture of polyesters, have generated color problems in the resulting polyester.

Polyesters are obtained by esterification, ester exchange or polycondensation of dibasic acids such such as terephthalic acid and isophthalic acid or esters of themselves, functional derivatives of hydrochloric acids and glycols such as ethylene glycol and tetramethylene glycol or oxides thereof and functional derivatives of carbonic acid derivatives. In this case, a single polyester is obtained when a component of a dibasic acid and a glycol component. Can be obtained mixed copolyesters when at least two or more types of components of dibasic acid and glycol are mixed, esterified or subjected to ester exchange and then undergo polycondensation. When a single polyester or two or more initial polycondensates of a mixed copolyester undergoes polycondensation, a neat polyester. In this invention, the term polyester designates in general to these three types.

The previous literature discloses titanyl oxalate compounds for use as polycondensation catalysts for polyesters. The disclosed titanyl oxalate compounds include potassium-titanyl oxalate, ammonium-titanyl oxalate, lithium-titanyl oxalate, sodium-titanyl oxalate, calcium-titanyl oxalate, strontium-titanyl oxalate, barium-titanyl oxalate, titanyl-zinc oxalate, lead-titanyl oxalate. However, based on the examples of such reference literature, only potassium-titanyl oxalates and ammonium-titanyl oxalates have actually been used to catalyze the polyester forming reaction. See for example, Japanese Patent Publication 42-13030, published on July 25, 1967. European Patent Application EP 0699700 A2 published 3/6/1996 assigned to Hoechst and entitled "Process for production of Thermostable, Color- neutral, Antimony-Free Polyester and Products Manufactured from it "discloses the use as a polycondensation catalyst, however only potassium-titanyl oxalate and titanium isopropylate have been used as catalysts, and, while disclosing a better colored polyester and without antimony, cobalt or optical brighteners have also been used. Other patents have disclosed potassium titanium oxalate as a polycondensation catalyst to produce polyesters such as US Patent 4,245,086, inventor Keiichi Uno et al ., Japanese patent JP 06128464, inventor Ishida, M. et al ., U.S. Patent 3,957,886 entitled "Process of Producing Polyester Resin" by Hideo, M et al ., In column 3, line 59 to column 4, line 10, contains a disclosure of titanyl oxalate catalysts for polyesters, including a list of many types of titanyl oxalate catalysts. However, in the examples only potassium titanium oxalate and ammonium titanyl oxalate and lithium titanyl oxalate are not even listed among their preferred titanyl oxalate catalysts.

The present invention is based on the discovery of non-titanyl oxalates to enhance the catalytic function of titanyl oxalate catalysts. The invention provides a new catalyst composition containing a titanyl oxalate catalyst and a metal oxalate catalyst enhancer optionally containing a metal cocatalyst such as an antimony based catalyst. A synergistic relationship between the titanyl oxalate catalyst and the catalyst enhancer has been discovered. A synergistic relationship between the titanyl oxalate catalyst, the catalyst enhancer and a metal cocatalyst such as antimony oxide or antimony triacetate has also been discovered. An improved process is also provided for producing polyesters by polycondensation of polyester forming reagents in the presence of a catalytically effective amount of a polycondensation catalyst, wherein the improvement comprises using, as a polycondensation catalyst, a catalytic composition. containing a titanyl oxalate such as lithium titanium oxalate and a catalyst enhancer such as metal oxalate that does not contain titanyl such as lithium oxalate and optionally containing a metal catalyst such as antimony oxide or antimony triacetate. The process can produce an improved polyester that has a lower number of acetaldehydes and a good color. The composition of the titanyl oxalate / catalyst enhancer can be used as a polycondensation catalyst in combination with other catalysts to achieve synergistic catalytic activity. A combination of lithium titanyl oxalate, Li 2 TiO (C 2 O 4) 2, lithium oxalate, Li 2 (C 2 O 4) is preferred. {2} with antimony oxide or triacetate
antimony.

Detailed description of the invention

The production of polyesters by polycondensation of polyester forming reagents is fine known to those skilled in the art of polyesters. A Conventional catalyst for the reaction is antimony oxide. The present invention is based on the discovery of a relationship synergistic between the catalysts of titanyl oxalate and a metal oxalate catalyst enhancer (for example, lithium oxalate) which is surprisingly superior in its performance as a catalyst for the reactions of polycondensation Some embodiments may produce polyesters. of a higher color (white) compared to others titanyl oxalate catalysts. That is why the need for a catalyst containing antimony, and you can produce polyesters without antimony with oxalate lithium titanyl as catalyst. Such advantages provided when using oxalate Lithium-titanyl are preserved when using oxalate lithium titanyl in combination with others polycondensation catalysts to produce polyesters. Preferably lithium titanyl oxalate constitutes at least one part per million (preferably 1 to 20) in based on the weight of titanium in the reaction mixture. Included in of the meaning of the term "oxalate lithium-titanyl "as used herein memory are dilithium titanyl oxalate Li 2 TiO (C 2 O 4) 2 and the oxalate of monolithium-titanyl where one of the lithiums of the titanium oxalate dilithium is replaced by another alkali metal such as potassium (for example, LiKTiO (C 2 O 4) 2, and such compounds with or  without hydration water. The oxalate catalysts of lithium titanyl can be combined with the catalyst of antimony to get the benefits of both catalysts when the elimination of antimony is not a requirement of resulting catalyzed product.

In addition to enhancing the catalytic effect of titanyl oxalates in catalyzing the reactions of polycondensation, metal oxalates can enhance the catalytic efficacy of titanyl oxalates in catalyzing of the esterification and transesterification reactions when they are used in catalytically effective amounts, with reagents that are known to participate in the reactions of esterification or transesterification. An effective amount since Catalytic point of view is enough. Are preferable approximately 3 parts of titanyl oxalate based on weight of titanium per million parts of reaction mixture of esterification or transesterification.

Reagents that form polyesters through a polycondensation reaction are well known to those skilled in the art and are disclosed in patents such as US Pat. 5,198,530, inventors Kyber, M. et al ., U.S. Patent 4,238,593, inventor B. Duh, U.S. Patent 4,356,299, inventors Cholod et al . And US Patent 3,907,754, inventor Tershashy et al ., Whose disclosures are incorporated as references. The technique is also described in "Comprehensive Polymer Science," Ed. GC Eastmond, et al ., Pergamon Press, Oxford 1989, vol 5, p. 275-315 and RE. Wilfong, J. Polym. Science, 54 (1961), p. 385-410. A particularly important commercial species of polyester produced in this way is polyethylene terphthalate (PET).

Titanyl Oxalates: Titanyl Oxalates include titanyl metal oxalates [M 2 TiO (C 2 O 4) 2 (H 2 O) n]  in which each M is independently chosen from potassium, lithium, sodium and cesium such as lithium titanyl oxalate or potassium titanyl and titanyl oxalates not metallic, such as ammonium titanyl oxalate. He Titanyl oxalate can be anhydrous (n = 0) or contain water of hydration, that is n represents the amount of water hydration.

Oxalates that do not contain titanyl: Oxalates without titanyl that function as catalytic enhancers of titanyl oxalate catalysts include lithium oxalate, Li 2 C 2 O 4, sodium oxalate, Na 2 C 2 O 4, potassium oxalate, K2C2O4, rubidium oxalate, Rb 2 C 2 O 4, cesium oxalate, Cs 2 C 2 O 4. Lithium oxalate is preferred.

Cocatalysts: Cocatalysts that they work in combination with the titanyl oxalate catalyst and The metal oxalate enhancer may include triacetate antimony, Sb (CH 3 COO) 3 glycoxide antimony, Sb 2 (OCH 2 CH 2 O) 2, oxide of antimony (Sb 2 O 3).

An effective amount to enhance the Catalytic activity of titanyl oxalate catalysts is at least about 1 part metal oxalate per part of titanyl oxalate catalyst. It is preferably from about 1 to about 100 parts of enhancer by catalyst based on total catalyst weight titanyl oxalate and cocatalyst, if present.

An amount of titanyl oxalate is added catalytically effective to reagents that They form the polyester. It is preferred from about 1 to approximately 40 parts per million catalyst based on weight of titanium in the catalyst and the weight of reagents that form the polyester, which is about the same as 1 part to 40 parts per million by weight of the catalysts in the resulting polyester based on the weight of titanium in the catalyst.

The following examples show the synergistic performance of the catalyst enhancer in combination  or one or more catalysts for a polycondensation reaction for the production of PET resin.

Examples

The catalyst evaluation was performed in a 1.5 L reactor, 3/16 stainless steel, fitted with a screw of extrusion at the base of the reactor. The vessel was equipped with three input ports and stirred vertically with an engine electric with amperage control. Laboratory experiments they were all performed on a 4.0 mol scale, using as polyester reagent reagent, BHET and an autoclave container of normal bottle resin. The experimental catalysts were added at the time of loading the BHET.

Bis (2-hydroxyethyl) terephthalate (BHET) and catalyst were added to the reactor and the contents purged with nitrogen. The mixtures were heated under reduced pressure with constant stirring. The EG produced during the polymerization was removed and collected. The polymerization stopped when the agitator's turning moment had reached a level, indicated by the amperage in the agitator motor, being normal for a polymer of
IV ~ 0.6.

Seventeen examples were carried out using the previous procedure and different amounts of catalysts and of catalyst enhancers.

Catalyst of example A - 240 ppm of antimony of antimony oxide (Sb 2 O 3) - reaction time = 127 min.

Catalyst of example B-10 ppm of titanyl of lithium oxalate - reaction time = 100 min.

Catalyst of Example 1-10 ppm Titanyl of lithium oxalate + 146 ppm of lithium oxalate (or approximately 15 equivalents) - reaction time = 53 min.

Catalyst of Example 2-10 ppm Titanium of lithium titanyl oxalate + 735 ppm oxalate lithium (or approximately 70 equivalents) - reaction time = 55 min.

Catalyst of Example C - 6 ppm Titanium lithium titanyl oxalate + 75 ppm antimony in antimony oxide (Sb 2 O 3) - reaction time = 105 min.

Catalyst of Example D-6 ppm Titanium lithium titanyl oxalate + 150 ppm antimony from antimony oxide - reaction time = 110 min.

Catalyst of Example 3-6 ppm Titanium lithium titanyl oxalate + 75 ppm antimony in antimony oxide + 367 ppm lithium oxalate (or approximately 15 equivalents) - reaction time = 65 min.

Catalyst of Example 4-3 ppm Titanium lithium titanyl oxalate + 38 ppm antimony in antimony oxide + 184 ppm lithium oxalate (or approximately 35 equivalents) - reaction time = 90 min.

Catalyst of Example 5 - 2.6 ppm Titanium of lithium titanyl oxalate + 33 ppm antimony in antimony oxide + 160 ppm lithium oxalate - time of reaction = 110 min.

Catalyst of Example 6 - 3 ppm Titanium lithium titanyl oxalate + 38 ppm antimony in antimony oxide + 185 ppm lithium oxalate - time of reaction = 95 min.

Catalyst of Example 7 - 3.3 ppm Titanium of lithium titanyl oxalate + 41 ppm antimony in antimony oxide + 146 ppm lithium oxalate - time of reaction = 70 min.

Catalyst of Example 8-2.0 ppm Titanium of lithium titanyl oxalate + 25 ppm antimony of antimony oxide + 90 ppm lithium oxalate - time of reaction = 120 min.

Catalyst of Example 9-4.7 ppm Titanium of lithium titanyl oxalate + 59 ppm antimony of antimony oxide + 118 ppm lithium oxalate - time of reaction = 100 min.

Catalyst of Example 10-2.0 ppm Titanium of lithium titanyl oxalate + 25 ppm antimony in antimony oxide + 50 ppm lithium oxalate - time of reaction = 125 min.

Catalyst of Example 11 - 2.0 ppm Titanium of potassium titanium oxalate + 25 ppm of antimony of antimony oxide + 90 ppm potassium oxalate - reaction time = 115 min.

Catalyst of Example 12 - 2.0 ppm Titanium of potassium titanium oxalate + 25 ppm of antimony of antimony oxide + 50 ppm lithium oxalate - reaction time = 165 min.

Catalyst of example E - 240 ppm of antimony of antimony oxide, commercial color adjustment included - reaction time = 110 min.

Results of the examples and discussion

It was observed that the catalysts with enhancer generated greater productivity, greater brightness, a coloration higher yellow and in most cases, lower levels of acetaldehyde (AA) in the polymer.

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When comparing example B with example 1, note that the addition of lithium oxalate to the oxalate of lithium-titanyl produces a doubling of the polymerization rate with respect to that achieved using only lithium oxalate. The polymers formed had a color, a concentration of acetaldehyde and a similar number of CEG. He added an extra amount of lithium oxalate as in the case of example 2, in relation to the amount present in the example 1, the polymerization rate did not increase further, indicating the presence of a synergistic relationship between oxalate lithium titanyl and lithium oxalate. When comparing examples B, 1 and 2 with example A, a greater polymerization rate in the former, with loads less than metal, than in example A, with an IV of the polymer, CEG number and similar acetaldehyde concentration and higher values of L * and b * for the first.

When comparing example C with example 3, the addition of lithium oxalate to the oxalate mixture of lithium-titanyl and antimony oxide, increased from significantly polymerization rate. They occurred polymers with similar CEG numbers and concentration of acetaldehyde However, Example 3 produced a polymer with higher value of L * and lower value of b * than those produced by the example C.

When comparing example C with example 4, where Titanium and antimony levels have been halved, the addition of lithium oxalate in example 4 provides greater polymerization rate with a titanium / antimony charge of 50%, evidencing directly the oxalate capacity of lithium increase the catalytic activity of the mixture of titanium and antimony catalyst. In addition, the concentration of acetaldehyde in the polymer produced with example 4 is considerably lower than in example C. The improvement was also improved color as indicated by the change in the values of L * and b *.

Examples 5 to 12 are compared, which consist in mixtures of titanyl oxalates, metal oxalates and oxide of antimony, with example E, which is antimony oxide with the added of a commercial color adjustment. The Similar polymerization rates for all examples. Without However, the three component catalyst blends of the Examples 5 through 12 all have a smaller metal charge. Too, the concentration of alceltaldehyde in polymers produced with Examples 5-12 is lower (up to 50%) than that observed in the control, example E, having the polymers Produced a good color.

The addition of a commercial color adjustment to antimony oxide control, example E, has the effect of reduce both the L * values and the b * vouchers (that is, the brilliance and yellow color) of the polymer produced. If I dont know I would have added the commercial color adjustment to this control, the L * and b * values of the polymer produced would have had values similar to those obtained in examples 5 through 12.

The most preferred catalyst is the mixture catalyst of example 10. This gave good color (L * and b *), time polymerization equivalent by comparison with the control, and considerably reduced AA in PET at low levels of catalyst.

Obtaining higher levels of polymerization, reduction of acetaldehyde in resins, and a reduction of antimony and the total catalyst, with effective repercussions on cost, are some of the advantages of the present invention, such As shown in the examples.

The results of the 17 examples are shown in The table that follows. It is worth noting that all catalysts (with the exception of example 12) demonstrated a better productivity in polymerization of BHET compared to the example of the standard antimony catalyst of example A and E. All produced brighter but more yellow products and CEGs of all lots were in the range 17 ± 7, which is typical for our autoclave laboratory processes. The acetaldehyde values for polymers containing titanium are typically higher than for polymers that contain antimony. However, it has been seen that the catalysts of Examples 4 to 12 produced polymers with an amount significantly lower acetaldehyde compared to controls containing antimony, which were achieved with levels very low catalyst (25% or less metal content when they were compared to the control).

The examples are divided into two groups. Examples AD and 1-4 refer to the synergy between lithium titanyl oxalate and lithium oxalate, lithium titanyl oxalates and lithium oxalate and antimony, which produce a significant improvement in polymerization rate. . Examples E and 5-12 indicate that when the quantities of the 3 components are optimized, they produce a catalyst with a speed equivalent to that of the control with a considerably lower metal load, producing a polymer that has a good color and a lower content
From aa.

one

Acetaldehyde concentration: AA is a undesirable byproduct of polymerization. Compare the levels 26 ppm AA of the 3 component catalyst (example 10) with those observed for control with antimony oxide (example E), of 48 ppm.

Polymerization rate: speed at which the reaction occurs, the measurement taken in this case when IV It was about 0.6. Compare polymer production with> 0.6 of the 3 component catalyst (example 4), time of reaction 90 minutes, with polymer production with IV> 0.6 of the antimony oxide (example A), with a reaction time 127 minutes

Intrinsic viscosity (IV): Indicates the degree of polymerization that occurred during the reaction. IV of 0.6 indicates a number average molecular mass of? 19,000.

CEG: terminal carboxyl group, which indicates the number of terminal acid groups per unit of polymer weight. Compare the 3 component catalyst (example 10) that produces a polymer with CEG level of 13 with that of antimony oxide with a CEG level of 14, indicating that polymers produced with both systems are similar from a structural point of view.

Catalyst concentration: The catalyst 3 components of Example 10 produced a polymer containing 34 ppm of metal derived from the catalyst, compared to the polymer produced with antimony oxide containing 240 ppm of metal catalyst derivative.

Claims (13)

1. Improved catalytic composition of oxalate Enhanced titanyl comprising titanyl oxalate, an oxalate metallic that does not contain titanyl in an amount effective to improve the catalytic efficiency of titanyl oxalate, and also optionally a metallic catalyst compound. 2. A composition according to claim 1 which further comprising said catalyst metal compound, is chosen between antimony triacetate, Sb (CH 3 COO) 3, antimony tris glycoxide Sb 2 (OCH 2 CH 2 O) 2, oxide of antimony (Sb 2 O 3). 3. A composition according to claim 1 or 2 wherein the metal oxalate containing no titanyl is selected between lithium oxalate, Li2C2O4, sodium oxalate, Na 2 C 2 O 4, potassium oxalate, K 2 C 2 O 4, Rubidium oxalate, Rb2C2O4 and Cesium oxalate, Cs_ {2} C_ {2} {4}. 4. A composition according to claim 1, 2 or 3 in which the titanyl oxalate is selected from oxalates titanyl formula M 2 TiO (C 2 O 4) 2 (H 2 O) n where M is independently selected from potassium, lithium, sodium, cesium and non-metallic cations such as ammonium, and where n (which can be 0) represents the amount of water from hydration. 5. A composition according to claim 1 or 2 in which the metallic oxalate that does not contain titanyl is oxalate of lithium and titanyl oxalate is oxalate of lithium titanyl. 6. A composition according to claim 1 or 2 wherein the titanyl-free oxalate is potassium oxalate and the titanyl oxalate is oxalate of potassium titanium. 7. A composition according to any one of the preceding claims wherein the metal oxalate which does not Contains titanyl constitutes from 1 part to 100 parts by weight of the Catalyst composition, by weight part of the oxalate of titanyl and any other metal catalyst compound. 8. A composition according to claim 7 in which the metal oxalate containing no titanyl constitutes 1 part to 80 parts by weight of the catalyst composition, by part by weight of the titanyl oxalate and any other compound metallic catalyst 9. A process for the production of a polyester by catalyzed polycondensation of the reagents that form the polyester in the presence of a polycondensation catalyst comprising titanyl oxalate, characterized by the use of a metal oxalate containing no titanyl with the titanyl oxalate to increase the catalytic effect of this, optionally another metal catalyst compound. 10. A process according to claim 9 in the than the titanyl oxalate, the oxalate that does not contain titanyl and the other additional optional catalyst are as defined in any one of claims 2 to 8. 11. A process according to claim 9 or 10 in which the amount of titanyl oxalate catalyst is from 1 to 40 parts per million based on the weight of Ti in the catalyst with regarding the weight of the reagents that form the polyester. 12. A process according to claim 9, 10 or 11 in which the polyester product is polyethylene terephthalate. 13. A process according to claim 12 in the that the polycondensation is of bis (2-hydroxyethyl) terephthalate.